Controlling-switch for electric motors



(No Model.) s Sheets-Sheet 1. W. J. POHLMAN. CONTROLLING SWITGH FOR ELECTRIC MOTORS. N0. 544,236.

Patented Aug.6,1895;

klvzan.

(No Model.) I 3 Sheets--Sheet 2.

W. J. POHLMAN.

I I CONTROLLING SWITCH FOR ELECTRIC MOTORS.

No. 544,236. Patented Aug. 6,1895.-

" m. vat/W" (No Model.) 3 Sheets-$heet 3 W. J. POHLMAN. CONTROLLING SWITCH FOR ELECTRIC MOTORS. No. 544,236.

Patented Aug. 6, 1895.

llwrrno STATES PATENT ()FFICE.

WILLIAM J. POHLMAN, OF WOODBROOK, ASSIGNOR or ONE-HALF TO J. EDGAR oRRI'soN, or BALTIMORE, MARYLAND.

CONTROLLING-SWITCH FOR ELECTRIC MOTORS.

SPEGIL'FICATION forming part of Letters Patent No. 544,236, dated August 6, 1895.

Application filed June 4, 1895. Seiial No. 551,669- (No model.)

To all whom it mag concern:

Be it known that I, WILLIAM J. POHLMAN, a citizen of the United States, residing at Voodbrook, in the county of Baltimore and State of Maryland, have invented new and useful Improvements in Controlling-Switches for Electric Motors, of which the following is a specification.

My invention relates to that type of con-' trolling-switch for electric motors which is shown in the United States Letters Patent granted to me upon the 29th day of January, 1895, No. 533,318.

It is the purpose of my present invention to provide a controlling-switch capable of being operated by a slight movement of the operators finger without interfering with or arresting the work being done, the action of said switch being wholly electric for the purpose of starting the motor, for stopping the same instantaneously, or reversing the direction of revolution of the armature and, as a consequence, of the dental or other tool driven by the motor.

It is a further purpose of said invention to provide a rheostat series or a succession of equal resistances so arranged that the whole or any partof the Whole series may be interposed in the circuit which feeds the motor, in order to graduate the speed according to the special requirements of the work to be done, and to so connect the said rheostat series relatively to the switch that by operating the latter the resistances may be wholly cut out at any moment by shunting the current around the same, thereby causing the motor to operate at full speed for any required interval, the resistances being again thrown into the circuit the instant the finger is removed from the switch.

It is my purpose also to simplify and improve the construction and operation of the switch shown and described in my Letters Patent granted the 29th day of January, 1895, No. 533,318, in such manner that the switch shall be electrically controlled, in contradistinction to the mechanical controlling devices described and shown in said patent.

The invention consists, for the purposes stated, in the novel features of construction and new combinations of parts hereinafter fully explained and then particularly pointed out and defined in the claims which follow and conclude this specification.

To enable those skilled in the art to which my invention pertains to fully understand and to practice the same, I will now proceed to describe said invention in detail, making reference for this purpose to the accompanying drawings, in which Figure 1 is a plan view of the housing or casing containing the operative parts. Fig. 2 is a front elevation of the same. Fig. 3 is a central vertical section from side to side. Fig. 4. is a plan view of the parts shown in Fig. 3, the housing being removed. Fig. 5 is a horizontal section taken through the binding-posts in Fig. 3. Fig. 6 is a section in a plane parallel to that in Fig. 5, but at a lower point. Fig. 7 is an inverted plan view of the housing, showing the binding-posts for the several wires to and from the batteries and through the electrically-operated mechanism. Fig. 8. is a plan view of the interior face of the closed top of the housing seen in Figs. 1, 2, and 3, showing the rheostat series and the switch-arm for cutting in or out one or more members of said series. Fig. 9 is a detail plan view showing the electromagnet and its armature. Fig. 10 is a detail perspective showing one of the switch-contacts to illustrate the construction by which it is detachably connected to the contact-fork on the'bindingpost through which said switchcontact has electrical communication. Fig. 11 is a detail perspective view of the switch-actuating arm. Fig. 12 is a detail view of the gear-segment and pawl by which the action of the switch is produced. Fig. 13 is a perspective view showing the clasp which surrounds the tool and carries the rocking contact, together with the flexible cords and their clips. Fig. 1 1 is a sectional view of the rocking contact, showing the means for centering the same. Fig. 15 is a diagrammatic View showing the battery, the switch, the flexible cords, and the tool operated by the motor. Fig. 16 is a diagram showing the arrangement of circuits.

The reference-numeral l in said drawings indicates a bracket or other suitable support, from which is suspended an electric motor 2 of any known or preferred type. Concentric ICU with the armature of said motor is a hollow tube 3, through which extends the flexible shaft, the latter being connected to the armature of the motor in the usual manner,whereby rotary motion is communicated through said shaft to a tool 5 at. the end of the flexible shaft. This tool may be of any formsuch, for example, as a dental instrument, secured in a hand dental instrument 6, which requires rotary movement at a greater or less speed, according to the character of the work. These partsthat is to say, the bracket 1, the flexible shaft, and hand instrumentmay be ofany known construction suitable for the purpose, and the electric motor may be of any known type. These parts, therefore, require no further special description.

I prefer to suspend the motor from the bracket by a coiled spring 7, of suitable ten sion, so that it may have free movement in accommodating itselfto the various movements of the instrument. Of course, however, any other suitable form of support may be substituted for the spring.

Projecting from the motor casing or frame is a rigid tubular stem 8, to the outer end of which the hollow tube 3 is connected. This stem incloses the end of the flexible shaft 4,

which is adjacent to the motor, and also cov ers the end of the armature-shaft, to which the end of the flexible shaft 4 is attached. I prefer to mount the controlling-switch upon the rigid tubular stem 8, as this arrangement makes the entire apparatus compact, simple, and more easily handled should it be desired to remove the same from one place to another.

and at any distance from the motor.

The parts constituting the controllingswitch are contained within a hdusing or casing 9 of cylindrical form, its lower open end being screwed into a narrow flange 10, which rises from the edge of a base-plate 12. Upon its lower face this base-plate is provided with a clamping-yoke 13, which surrounds the rigid tubular stem 8. The ends of the yoke are bent in opposite directions and receive screws 14, which are tapped into the base plate, thereby drawing the stem 8 into notches or depressions in a flange 15, which drops from the lower or bottom face of the baseplate. This flange gives a firm support for the stem 8 and holds the latter away from the bottom of the base-plate. The flange 15 is cut away at points diametrically opposite each other and half-way between the notches which receive the stem 8 to give spaces 16 for the screws 14.

Through the center'of the base-plate 12 passes a pivot 17, upon the upper end of which is rigidly mounted a ratchet 18, heneath which, but loosely mounted on the same pivot 17, is a segmental or mutilated gear 19, provided with a projecting arm 20, on which is pivoted a push-pawl 21, which engages the teeth of the ratchet 18. The teeth of the mutilated gear 19 mesh with teeth upon the end of an arm 22, which is loosely pivoted at its other end upon a post 23 placed near the outer edge of the base-plate. A spring 21-, coiled upon a sleeve surrounding the post 23, throws the arm 22 in such direction that, after each movement of the ratchet 18, said arm will turn the mutilated gear 19 back to its original position, the push-pawl 21 being drawn over the ends of the teeth on the ratchet. The pivoted end of the arm 22 is provided with a sleeve 25, which surrounds the post 23, and on the upper end of the sleeve is a leverarm 26, which extends in parallelism with the arm 22, and is the device by which the said arm is operated. The means for operating it will be explained hereinafter.

Upon the ratchet 18, but electrically isolated by an insulating material 27, are mounted two electrical contacts 28 and 29, parallel with each other, but upon opposite sides of the pivotal axis of the ratchet. These contacts consist, preferably, of strips of conducting metal of any suitable kind-such, for example, as copper or brass-the ends of each strip being bent to surround pins 30, which rise from the upper face of the insulation 27 on the ratchet 18. This construction enables the contacts, when worn, burned out, or otherwise injured to be readily removed and new contacts substituted. It will be noted from Fig. 5 that the four pins 30, which support these two con tacts, are placed substantially at four points which are equally distant from the axis ofthe pivot 17.

The contacts 27 and 28 lie within a substantially rectangular space, which is inclosed by four independent brushes 31, 31 1,31", and 31, mounted upon separate posts not far from the edge of the base-plate 1.2. Each brush is provided with a slotted or forked end 33, as seen in Fig. 10, which is slipped between two similar clamps 31, which project from a collar 35, loosely mounted on one of the posts 32. The slot in the end of the brush permits it to pass a screw 36, which passes through one of the clamps 3i and is tapped through the other, so that by merely loosening the screw the brush can be drawn out from between the clamps and a new one inserted in its place, thereby avoiding the necessity of removing the screw entirely. The free ends of the brushes are provided with downwardly-projecting lugs 37, which have bearing upon the peripheryol' the insulating disk 27, as shown in Fig. The brushes be ing elastic their constant normal tendencyis to maintain a slight pressure of those lugs against the edge of the disk, while a small curvature given to said brushes causes them to pass just far enough within the periphery of the insulating-disk, so that when the latter is turned to cause the contacts 27 and 28 to assume the position shown in Fig.16 the ends of each contact will engage two of the brushes 31, and the contact will then form a bridge for the current and enable it to traverse both the brushes thus engaged. In order to maintain this contact and to keep the brushes constantly pressed toward the pivotal center, I prefer to mount the collars upon screwpivots 38, tapped into the upper ends of the posts 32, fastening them by washers 39, interposed between the collars and the heads of the screws. Coiled springs 40, coiled upon the posts 32, exert a constant elastic force, by which the collars are so turned as to press the brushes toward the center of the disk.

Risingfrom the base-plate 12, near the outer edgev and upon opposite sides of a diametrical line, are two uprights 41, connected byia Z-shaped strip 42,,parallel with the base-plate and preferably integral with the uprights.

The ends of the strip 42 form supports for the cores 43 of two electromagnets, which are' wound by the same wire, but in opposite directions, so that their polaritywill be reversed. At the central point of the strip 42 is a vertical enlargement, in which lies the pivotal bearing 44 of an armature 45, the ends of which are bentin opposite directions, as shown in Fig. 9, whereby one of said ends will lie near and substantially parallel with the beveled face of one end of the core 43 of one magnet, while the other and similar end will stand in like relationsto the similarly formed, but opposite end of the core of the other magnet. Thus, when a current traverses the wire common to both cores, both ends of the armature will be attracted simultaneously andvin about the same degree. Projecting from one end of the strip is a small lug 46, inwhich is mounted a finger 47, which hangs close beside the lever-arm 26, as seen in Fig. 4, and not far from the post on which said arm is pivoted. It will readily be seen that by reason of its position a comparatively slight movement of said finger 47 will effect a much greater movement of the toothed end of the arm 22, Fig. 5. Thus when the circuit of the electro magnets 43 is closed and the armature 45 is attracted a movement of the arm 22 and mutilated gear 19 will be produced of such extent that the ratchet 18 will be turned by the push-pawl 21 one-eighth part of a full revolution or a distance corresponding to an arc of forty-five degrees. If the contacts 28 and 29 are in the position shown in Fig. 5, in which they are removed from electrical contact with the brushes 31, 31, 31

and 31, the vibration of the armature of the magnets will so far advance the ratchet 18 and disk 27 as to bring th'econtacts 28 and 29 into the position shown in Fig. 15, in which the contact 28 has electrical contact with the two brushes 31 and 31, while the contact 29 has a similar electrical engagement with the I two brushes 31 and 31.

The circuit of the two electromagnets 43 is completed through two posts 48 and 49, the

former rising from the post 32, which carries the brush 31, and the latter being mounted on an independent support 50 arranged between the two posts 32, which carry the brushes 31 and 31, Figs. 4, 5, and 15. The support 50 is insulated from the base-plate 12 by an interposed cushion 51, of any suitable insulating material, and is fastened by a screw 52, passed through the base-plate 12 and tapped into the support 50. The screw 52 is also insulated from the base-plate by means of an insulating-bushing 53 and a segmental plate 54, of hard rubber or other suitable insulating material, which is interposed between the head of the screw 52 and the lower face of the base-plate 12. Between the head of the screw and said insulating-plate 54 is inserted an-angular bracket 55, one end of which is turned downwardly and provided with a vertical slot 56, which has a widened portion 57 at its end, for a purpose presently to be explained.

The post 48 is mounted on one of'the posts 32, as already mentioned, and said post 32 is electrically isolated from the base-plate in substantially the same manner already ex plained in connection with the support 50. An angular bracket 58 is in like manner inserted between the head of the screw which fastens the post to the base-plate and an insulating segmental plate 54, similar in form' and func- 4 tion to the plate 54 on the other side of the center of the base-plate. The post 32, which carries the brush 31 is similarly insulated from the base-plate and is provided with an angular bracket 59, resembling in construction the brackets 55 and 58. The post 32, carrying the brush 31, is similarly insulated and provided with a like angular bracket 60, and the fourth post, carrying the brush 31, has a bracket 61 and alike insulation from the baseplate.

Upon the hand instrument 6 is mounted a clasp 62. (Shown in detailin Fig. 13.) This clasp is provided with a pair of elastic clamping-lugs 63, which afford convenient means for the attachment of a curved plate 64, the latter having a tongue 65, which is pushed between the clasp and the lugs. The curved plate 64 is formed of any suitable conducting metal, and from its outer or convex face rise two lugs 66, upon which is pivotally mounted a sector 67, the outer convex face of which is milled or roughened to give suitable contact for the finger or thumb of the operator. Projecting from one end of the sector are two contact-points 68 and 69, one on each side of the pivotal axis of the sector and at substantially the same distance from it. Upon the curved plate 64 is mounted an insulatingblock 70, of hard rubber or other suitable material,'in which are mounted three separate contacts 71, 72, and 73. The two first are so arranged that by rocking the sector 67 upon its pivotal axis 67 the contact-point 68 may be brought upon the contacts 71 and 72 simultaneously, and by rocking the sector in the opposite direction the contact-point 69 may be brought against the contact 73. The curved plate 64 is in electrical connection with the sector 67 and with both of its contact-points G8 and 69, as indicated in Fig. 16. Inits normal position the sector 67 is held by a spring 7 1, coiled on its pivotal support 67, as shown in Fig. 16, with both contact-points 68 and 69 about equally removed from the two contacts 71 and 72 on one side and from the contact 73 on the other side of the pivotal axis.

Vithin the closed top of the casing or housing 1 is arranged a variable rheostat or resistance series, consisting of successive resistance-coils 75, arranged in a circle. I prefer to use German silver wire for these coils, though I may use any other suitable metal. In the center of the closed top of the housing is an insulation 76, in which is pivoted a turnbutton 77, its shaft projecting into the housing, and having on the lower end a contactfinger 78, which sweeps over the whole series of resistance-coils, making contact with each.

From a support 79, insulated upon the baseplate in the manner already described, rises a contact-strip 80, which curves upward and inward until its end lies directly beneath the end of the shaft of the turn-button 77, and in such position that when the housing is screwed into the flange of the base-plate the said shaft will rest on and have electrical contact with the contact-strip 80.

At a suitable point in the rheostat series is placed a clasp 81, mounted on the pulp-ring which supports the series, and having an elastic contact-finger 82, which hangs somewhat below the resistance-coils, as seen in Fig. 3. 150th the clasp and the finger are of conducting metal, and they are in electrical connection with one end or terminal of the coil series.

Rising from the insulated post 32, on the base-plate 12, which holds the brush 31 is a contact-post 8 1-, so located that when the hous ing is in place the end of the contact-linger 82 will bear against the upper end of the contact-post 81. A small opening in the wall of the housing enables the operator to observe when this engagement is effected. The contact-strip and contact-post 8 1 have electrical connection with a bracket 85 and the bracket 59, respectively, secured to and insulated from the lower face of the base-plate 12, in the manner already described. These brackets are formed like the others for the purpose of securing the terminals of the several wires, each terminal consisting of a substantially-cylindrical piece of metal 87, Fig. 13, having a slot 88 formed in its end. A screw 89 passes through the arm on one side of the slot and is tapped into the other arm. In making the connection the bracket on the base-plate is caused to enter the slot 88 in the bracket and pass into the upper portion of said slot, while the solid end of the terminal 87 enters the widened portion of the slot in the bracket. The screw 89 is then turned to clamp the two ends of the terminal upon opposite sides of the slot 88 against the bracket.

I will now describe the several circuits, referring for this purpose to Fig. 16, which is a diagram of the same. The battery is indicated in said diagram by the letter 13, and starting from its positive pole a wire 90 goes to one terminal of the coils of the magnetic field. coils a wire 91 is led to the post which supports the brush 31. Following the circuit, which is completed when the contacts 28 and 29 are in the position shown in Fig. 16, a wire 92 is taken from the post carrying the brush 31 to one of the brushes of the motor, and from the other brush a wire 93 goes to the post supporting the brush 31. Thence, the current being bridged by the contact 2!),a wire 93 goes to the clasp 81 in the rheostat series, while from the contact-linger 78, or from the central shaft carrying said finger, the circuit is completed through the post 80 and over a wire 9i from said post to the other pole of the battery, thus making an operative electric circuit for the motor. From the wire 9 1. a shunt 95 is led to the curved plate (i l on the clasp 62, mounted on the hand-instrument. From the contact 71 a wire 96 is led to the post as, which is connected to one terminal of the coils of the electromagnets 13. From the contact 72 a wire 97 is led to the post carrying the brush 31, and the two contacts 72 and 73 are electrically connected together.

The operation is as follows: Let it be supposed that the apparatus is at rest, the parts of the switch being in the position shown in Fig. 5, in which the contacts 28 and 29 are off the brushes, and the battery circuit is therefore broken. If the operator new places his finger upon the sector (57 and rocksitslightly to bring the contact-point (38 on the contact 71 and 72, the battery-circuit, which includes the electromagnets :3, will be completed (starting from the positive pole) by wire 90 through the field-coils of the motor, by wire 91, electro-coils 13, post 49, wire 96, to contact 71. From this point the shortest path for the current is through the contactpoint 68, sector 07, curved plate 6 1, shunt 95, and wire 94, back to the other pole of the battery. This operation of the magnets turns the ratchet far enough to bring the contacts 28 and 20 into electrical engagement with the brushes, the extent of rotary movement being a distance slightly greater than the space separating the eight teeth upon the ratchet carrying the disk, This ratchet is held by a stop-pawl 27, mounted on an arm 28, which is pivoted on a post 29, a spring coiled on said post, or on a sleeve surrount'iing it and rigid with the end of the arm, presses the latter in a direction contrary to the rotation of the ratchet, the result being that the stoppawl 27 will be drawn ott the tooth it engages by the movement of the ratchet in excess of the one-eighth of a revolution, and being pressed by its spring the arm will fly back and engage the next tooth, thereby causing a slight retractile movement to the ratchet and leaving the contacts either in the position shown in Fi 5 or in the position From the second terminal of theseshown in Fig. 16, according to their previous position. In breaking the circuit this operation gives a sharp and instantaneous stop to the motor by causing a reversal of the current for an instant before it is cut out.

The circuit described above energizes the electromagnets 43 and causes them to attract the armature 45, which turns the disk carrying the contacts 28 29, bringing the latter into the position shown in Fig. 16, in which contact 28 has electrical engagement with the two brushes 31 and 31"", while contact 29 has like engagement with the two brushes 31 and 31. In this position the circuit is over wire 90, through the field-coils, wire 91, brush 31, contact 28, brush 31, and wire 92, to one brush of the motor-armature, thence by way of the other brush, over wire 93, brush 31, contact 29, brush 31 and wire 93 ,to the clasp 81 and contact-finger 82, thence through the rheostat-coils and contact-finger 78 and Wire 94, back to the second pole of the battery.

It will be noted that by turning the contact-finger 78 the whole rheostat series may be cut in or out, or. any part thereof may be included in the motor-circuit. By again rocking the sector 67 in the same direction to bring the contact-point 68 upon contacts 71 and 72 a second time, the current will again flow through the coil of the electromagnets t3 and the disk will be turned another step, whereby the contacts 28 and 29 will assume the position shown in Fig. 5, in which the circuit is broken. If, new, a third closure be made between the contact-point 68 and the contacts 71 and 72, the disk carrying the contacts 28 and 29 will again be advanced oneeighth of a revolution, whereby the contacts 28 and 29 will be brought into the position shown in dotted lines in Fig. 16, in which the contact 28 will bridge the current from brush 31 to brush 31 While contact 29 will bridge the current from brush 31 to brush 31. The circuit under this arrangement is so plain as to require no description, and as it flows in a direction opposite to that before described the revolution of the armature of the motor and of the instrument will be reversed.

It may, under some circumstances, be desirable to cut out the rheostat series without using the turn-button 77, and for this purpose I have provided the contact 73 and contactpoint 69. By bringing these together the circuit will be over wire 90, field-coils, wire 91, brush 31, contact 28, brush 31, wire 92, through the armature windings of the motor, over wire 93, brush 31, contact 29, brush 31 wire 97, contact 73, contact-point 69, sector 67, plate 64, shunt 95, and wire 9% back to the second pole of the battery.

It is evident that the conductors may conveniently be carried from the stem on the motor along the flexible shaft in any suitable manner, but I do not confine myself to such arrangement, as the position of the motor may be varied widely.

lVhat I claim is 1. The combination with an electric motor, of a controlling switch consisting of four independent brushes, a disk carrying two contacts arranged in a space inclosed by said brushes, means for intermittently revolving said disk a definite part of a revolution, a pivoted sector on the hand instrument having two contact points, three adjacent contacts two of which are adapted to be engaged by the contact points, alternately, the third contact being in permanent electrical connection with the sector, an electro-magnet, an armature for the same connected to and rotating the disk, a circuit for said magnet including one of the contact-points on the sector and one of the three adjacent contacts, and a circuit for the motor including the four brushes and the two contacts of the controlling switch, a rheostat series, and a contact finger movable over and in contact with said series,substantially as described.

2. The combination with an electric motor of a controlling-switch comprising a rocking, electrically conducting sector mounted on the hand-instrument and provided with two contact-points normally out of engagement with two corresponding contacts on the hand instrument, a third contact having permanent electrical connection with the sectorand both its contact-points, one or more electro-magnets, an armature attracted by said magnets, four independent brushes arranged substantially at right angles one to another, two parallel contacts arranged and insulated in the quadrangular space inclosed by the four brushes, the insulating support being connected to the pivotal axis of the magnetically attracted armature, and a circuit for the electro-magnet including a contact-point on the sector, a contact on the hand-instrument, and the field-coils of the motor, substantially as described.

ICC

3. The combination with an electric motor of a controlling switch, comprising an electromagnet, an armature for the same, contacts which receive a definite movement by the vibration of said armature, brushes arranged about said contacts, a circuit making and breaking sector having contact-points normally out of engagement with adjacent contacts, a separate contact having permanent electric connection with the said sector and with one pole of a battery, and a circuit for the electro-magnet including one of the contact-points on the sector, the corresponding adjacent contact, and the separate, permanently connected contact, substantially as described.

4. The combination with an electric-motor of a controlling switch to start, stop, and reverse said motor, said switch consisting of a movable, electrically conducting, circuit-making and breaking sector having two contact points two adj acent contacts normally out of engagement with the said contacts, athird separate contact permanently connected to the sector and one pole of a battery, an electro-magnet having an armature turning when attracted upon a pivotal axis, two parallel contacts pivotally mounted and advanced a definite part of a revolution at each vibration of the magnetic armature, independent brushes surrounding said contacts and adapted to be engaged thereby, in pairs, at each alternate advance of the parallel contacts, a circuit for the electro-magnet including the field-coils ot the motor, the sector, one of the adjacent contacts and the third separate contact, and a circuit including the second contact point on the sector, the corresponding adjacent contact, two of the brushes, the armature-brushes of the motor, and the two remaining brushes, substantially as described.

5. The combination with an electric-motor of a controlling-switch consisting of a pair of parallel con tacts, electrically controlled means for turning said contacts one eighth, or other definite part of a revolution, four brushes arranged substantially at right angles, one to another, about said parallel contacts and electrically coupled in pairs at each alternate part revolution of the parallel contacts, a rocking, or movable circuit-making and breaking sector having two contact points, two adjacent contacts normally out ofcngage ment with the contact-points, a third contact permanently connected to the sector and one pole of a battery, a circuit for the electromagnet including one of the contact points on the sector and, one of the adjacent contacts, and completed through the field-coils of the motor, the battery and the third contact, and a circuit for the motor including the fieldcoils,two of the brushes, the armature of the motor, and the two remaining brushes, a resistance series having a contact finger movable over said series, and connected to one pole of the battery, and a shunt to the third, permanently connected contact around said resistance series, substantially as described.

In testimony whereof I have hereunto set my hand in presence of two subscribing witnesses.

WILLIAM J. 'IOI'ILMAN. lVitnesses:

ENooH I. OALLow, Jot-IN E. ORRISON. 

